Drilling Glass

[robertifly]

I recently drill 4 holes for 1" bulkheads and it went really very well except for one thing, where the drill came thru the other side of the glass the holes broke out a little instead of a smooth edge. I thought I went slow enough but maybe not. Anyone know what causes that problem? I have a couple more larger ones to drill and would like to get smoother holes, thanks.

[MayorOfWhoVille]

I believe it happens because there is no support underneath the glass. When you are almost all the way through the glass the last little bit actually just breaks off. Let's say you could brace the glass from the inside, so that it is resting on a wooden support or something. This might help keep the glass from breaking through this last little bit. Does anyone else have experience with this?

[jcollins]

I agree. The same happens when you cut wood.

[SeaWeed89]

ive had this problem it can be done just extreamly slow slow speed and very little weight from the drill. also try just drilling from the inside if possible and if you get a chip atleast its not on the gasket side.
GOODLUCK

[SeaWeed89]

i have done a repair with automotive glass repair kit from my local auto store. it did a good job of making a flat spot were the chip was on the inside of the tank for the gasket.

[robertifly]

Thanks for the input, next two holes are 2" so I want as little breakout as I can get.

[lth03]

Did you constantly apply water while drilling the glass?It will help a lot for a smooth finish.I always take my tank to a shop in Orange County CA and the guy always put a ring,seal with silicone and put water with drill bit cooler gel in there and drill inside that ring with a drill look like a drill press but way smaller,the hole always smooth and perfect every time.

[flyingclay]

I have only drilled glass with a dremmel and diamond bit but from what I have heard if you angle it a little with back pressure from a wood block the water that is dammed up around the hole will drain in the one spot and you then know you are close to drilling all the way through. Then go even slower or lighter pressure. hope this helps.

[Rickey]

I have drilled quite a few with a bit. Make sure that when you do it that you keep water going over the bit at all times. I usually do it in the backyard and have my wife hold the water hose for me or tape the hose in a good position until I am done. I still get a few small chips now and then but usually it is pretty smooth. If you want to smooth it some you can take a dremmel and go around the edge after you are done.

[robertifly]

Yeah, I taped water hose in place to get constant water,,,maybe be the pressure right at the break thru point. Seems like I read where someone put tape on the back side but I'm not sure for what.

[MayorOfWhoVille]

Hmmm, maybe the tape could hold the glass in place so that it won't 'break' through leaving chips? Has anyone tried tape?

[xJake]

Tape is probably the best option for preventing this. It keeps the glass piece from snapping off prematurely. I believe AGA reef-ready aquariums are actually drilled from both sides of the glass simultaneously to prevent this.

[reefer96]

i used some plumbers putty to make a ring around the hole im going to drill (like a donut with the hole in the middle) and fill the center with water and then start drilling. it keeps the bit cool the whole time. i tape the undersideof the glass to keep the piece from falling and causing break out.

[robertifly]

I don't see how the putty dam could be better than a constant flow from a hose but I will use tape on the back side of the next two holes.

[reefer96]

not that its better, its an alternative, perhaps your drilling in your basement and dont want a mess:)

[MCary]

You can duct tape the other side, As stated before you need to be careful not to punch out the other side. When you close to the other side you need to take pressure off the drill. When you first cut through, the water will drain, if you can at this point you can turn the glass or tank and finish your cut from the other side. This will leave a clean edge.

[robertifly]

point well taken reef96, I hadn't thought of that. I was doing mine on the dirve next to the shop and the hose was right there.

[reefer96]

robertifly, I did this on my 6ft 150g, i put in a calflo style internal overflow box on one end of the tank making it a pennesula tank. I put in 3--1.5 in bulkheads, it took about 3 hours total to drill all 3 holes in .5in glass (that includes a few breaks by the way) i didnt want to carry that heavy thing anywhere else:)
and to think i was originally going to use a cpr overflow lol.

best decision in my build was to drill.

[scaast]

This is how I do it...clamp 1/4" acrylic front and back...I predrill the front acrylic so it acts as a guide and also holds the water for cooling.<br>
http://i107.photobucket.com/albums/m308/scaast/IM000946.jpg

[robertifly]

reefer96, do you have another box on the outside for collection and plumbing or just plumbed drains right out of the BHs? I really like the calflo system, I had it on the last tank coast to coast and think it does a good job skimming, I am just trying to use it on this tank and use a BeanAnimal style Failsafe and Silent Drain system.
scaast, I did that but only on one side with a acrylic guide, maybe if I had one on both sides and clamped there wouldn't have been any break out.

[LJA]

If the edges are rough after you drill, what is the best way to smooth them out? I'm planning on drilling my new 55gallon in about a week :D!

[bishop82476]

wheres the best place to get glass bits

[coralfragger101]

The cheap Ebay ones work just fine.

Last time I bought them I got a 3 pack set. Bits for 3/4, 1" and 1.5". It was like $25 WITH shipping.

[ThaNgBOm321]

not 100% sure but i think all standard 55 gallon tanks are tempered on all sides...

<a href=showthread.php?s=&postid=12845728#post12845728 target=_blank>Originally posted</a> by LJA
If the edges are rough after you drill, what is the best way to smooth them out? I'm planning on drilling my new 55gallon in about a week :D!

[LJA]

My 55 Gallon has a sticker on the bottom that says that the BOTTOM is tempered. I've been told that this means just the bottom.


Is this correct? Can someone please verify?

Also, my other question still stands :D

[robertifly]

OK I did it, the last hole came out pretty good with only very small chip if any really. I think the best advice is when it is about to break out take all the pressure off and let just the weight of the drill take it through. Some support underneath can't hurt either but I think "not pushing" did the trick.

[rugar20]

<a href=showthread.php?s=&postid=12849119#post12849119 target=_blank>Originally posted</a> by LJA
My 55 Gallon has a sticker on the bottom that says that the BOTTOM is tempered. I've been told that this means just the bottom.


Is this correct? Can someone please verify?

Also, my other question still stands :D

Well mine had the same sticker (orange in color) and I was told the same it is only the bottom but it was not true I started to drill my tank and with in a few seconds the whole back shattered into several small pieces. So my rec is call glass shops in your area and see if they have a way to test to see if glass is tempered or not before you start drilling

[sjm817]

Some 55Gs are tempered on all 5 sides as unfortunately, you found out. I believe AGA 55Gs are bottom only, but Perfecto are all 5 sides.

[Pescado Amigo]

I found that if you let the weight of the drill do the work, and not put any extra preassure that the holes come out great. I to have used the plumbers putty donut dam and mixed a little dawn dish soap for a lube. I have always had great success. i do like the acrylic guide though.

[sjm817]

Ditto on the pressure. Just let the weight of the drill do the work. Very gentle when you break through. I put a some duct tape on the inside to keep the piece from falling out.

I never used the putty dam. I drill the tank outside and just tape a garden hose to the tank and let a stream of water flow over the drilling area.

[Luis138]

Is there any way to know if the glass is tempered?

Luis

[robertifly]

Right on Pescado Amigo! When ready to break through - weight of the drill only!. I used a acrylic guide also which works very good as well, just didn't like the idea of holding the drill at an angle and free handing it, I could just see the hole saw skating across the glass and scaring it. The guide also allows you to position the hole accurately. Oh yeah, I always drill from the inside so any breakout will not affect the seal and I used the water hose running on the saw full time.

[randomworker]

<a href=showthread.php?s=&postid=12893471#post12893471 target=_blank>Originally posted</a> by robertifly
... Oh yeah, I always drill from the inside so any breakout will not affect the seal ...

That is an excellent tip. :)

[carb850]

<a href=showthread.php?s=&postid=12893302#post12893302 target=_blank>Originally posted</a> by Luis138
Is there any way to know if the glass is tempered?

Luis

I once read that if you look at tempered glass using polarized lenses that it will look different. I haven't tried this however.

[rugar20]

<a href=showthread.php?s=&postid=12895316#post12895316 target=_blank>Originally posted</a> by carb850
I once read that if you look at tempered glass using polarized lenses that it will look different. I haven't tried this however.

Not always true I know on auto glass that is tempered it does look different kind of spotty but on an aquarium it does not always look that way I shattered my aquarium by going by this theory. I looked at it and it did not look spotty so i figured it was not tempered but it was shattered into a hundred little piece when i started to drill it. I was told by someone after that to call my local glass repair shop and the may be able to tell. Some places have some kind of machine to tell whether or not glass is tempered

[Luis138]

I called this glass shop and asked them how to tell and they told me if it says tempered on it. Lol!!!

Luis

[1fishkeeper]

<a href=showthread.php?s=&postid=12896839#post12896839 target=_blank>Originally posted</a> by Luis138
I called this glass shop and asked them how to tell and they told me if it says tempered on it. Lol!!!

Luis

Well that was nice of them. Now Im starting to wonder if my tank that Im getting ready to drill is.